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Abstract

A focus on social deficits in autism spectrum disorders (ASD) has, for a long time, obscured the existence of lower-level perceptual abnormalities, although the earliest
descriptions of autism included abnormalities in oculomotor behavior and visual attention. More recently, however, abnormalities in perception and attention have increasingly been discussed as influential factors in ASD-specific psychopathology. To this end, the perception of coherent motion in random-dot kinematograms, biological motion in
point-light walkers and agency in animated shapes have been investigated in ASD but their relationship remains a matter of debate. It also is unclear whether ASD-related deficits result from difficulties in global motion perception or in processing motion that contains socially relevant signals (e.g. a body and actions). We tested 18 individuals with highfunctioning autism and 16 age-, gender- and IQ-matched control participants, who performed three tasks on a continuum of motion cues and social complexity: (1) low-level translational motion that moved up or down, (2) complex motion of a single dot that moved in an animate or
inanimate way, (3) complex motion of two dots that interacted or not. None of these tasks contained objects with human shape and only the first task contained global motion. Participants with autism were selectively
impaired in detecting social interaction between two animated shapes (task 3), while low-level motion processing (task 1) and the detection of isolated agents (task 2) were preserved. These findings suggest a distinct social impairment in ASD in understanding interacting agents.